1. Technical Field
The invention relates to data delivery and communication in personal electronic devices. More particularly, the invention relates to intelligently switching between communication protocols in personal wireless electronic devices.
2. Description of the Prior Art
Currently, the Short Message Service (SMS) is used by messaging services to communicate to wireless devices. SMS is provided by wireless carriers to the majority of their cell phone customers for text messaging, for example.
Referring to FIG. 1, SMS is used for sending and receiving messages between a messaging service 101 and a mobile device 104. Messages must be no longer than 160 alpha-numeric characters and contain no images or graphics.
SMS is a store and forward system. This requires that an intermediate be provided to perform the store and forward functionality. A Short Message Service Center (SMSC) 102 ensures the timely delivery of messages to mobile clients 104. Communications between mobile clients 104 and SMS transmission facilities 103 are transient due to the mobile nature of the mobile clients 104. A mobile client 104 may be momentarily unreachable because the mobile client 104 has entered into a tunnel or garage, for example. The SMSC 102 has the ability to detect that the mobile client 104 is not available and will wait until the mobile client 104 comes back online.
The SMSC 102 delivers any waiting messages when the mobile client 104 comes back online, i.e., communication is restored. Messages will typically wait for three days on the SMSC 102 before they are deleted.
However, SMS is expensive for the carrier to maintain and provide. What drives the carrier's cost is how much the carrier has to pay for the infrastructure and the cost of the bandwidth.
The General Packet Radio System (GPRS) is a packet switched data network for mobile Global System for Mobile Communications (GSM) and time-division multiple access (TDMA) users. Packet switching means that GPRS radio resources are used only when users are actually sending or receiving data. GPRS involves overlaying a packet based air interface onto the existing circuit switched GSM network.
The main benefits of GPRS are that it reserves radio resources only when there is data to send and it reduces reliance on traditional circuit-switched network elements. The available radio resource can be concurrently shared between several users rather than dedicating a radio channel to a mobile data user for a fixed period of time.
With respect to FIG. 2, a messaging service 201 using the GPRS system sends messages to a mobile client 203 through the GPRS transmission service 202. GPRS is not a store and forward system as with SMS. Messages are sent from the messaging service 201 to the mobile client 203. If the mobile client 203 is not online, then the message is dropped and the messaging service 201 knows that the mobile client is not available because it does not receive a response from the mobile client 203.
GPRS has theoretical maximum data speeds of up to 171.2 kilobits per second (kbps). This is about three times as fast as the data transmission speeds that are possible over today's fixed telecommunications networks and ten times as fast as current Circuit Switched Data services on GSM networks. By allowing information to be transmitted more quickly, immediately, and efficiently across the mobile network, GPRS is a less costly mobile data service compared to SMS.
GPRS facilitates instant connections whereby information can be sent or received immediately as the need arises, subject to radio coverage. GPRS facilitates several new applications that have not previously been available over GSM networks due to the limitations in speed of Circuit Switched Data (9.6 kbps) and message length of the Short Message Service (160 characters). However, radio coverage for GPRS is currently limited because of the slow proliferation of GPRS transmission equipment.
It would be advantageous to provide a message transmission system in a GPRS environment that provides robust delivery of messages to and from wireless device users, such as cellular phones, using both SMS and GPRS. It would further be advantageous to provide a message transmission system in a GPRS environment that provides the user and messaging provider the ability to balance the use of communication systems on a cost versus convenience basis.